Robin Williams had chemical substances in his system before he committed suicide.

The 63-year-old star hanged himself with a belt at his home in Tiburon, California yesterday (11.08.14) and also had ''acute, superficial cuts'' located ''on the inside of his left wrist'' from a pocket knife, according to the Marin County Sherif's Department.

During a press conference today (12.08.14), Lt. Keith Boyd confirmed the Oscar winner died from asphyxia due to hanging and chemical substances were found in his system during an autopsy after his body was discovered by his personal assistant.

Toxicology results will not be made available for approximately two-six weeks so further tests can be carried out.

Boyd said: ''His body was in a position that looks like he's sitting in a chair, slightly off the ground, suspended between the belt that was wedged between the door and the door frame.''

He added: ''We want to be thorough. We want to be sure that we cover all of our bases...to make sure we're not forgetting anything else that we're not being presumptive and overlooking [pertinent details].''

Police are continuing to investigate 'The Birdcage' star's death, and no time of death has been specified, but they confirmed his wife, Susan Schneider, was the last person to see him alive.

Robin reportedly sought treatment in rehab last month and his spokesperson confirmed yesterday that he had been battling ''severe depression'' recently.